I want to start by stating that I am not expecting much from the current iteration of the FE AI, as we know the AI is only partially implemented at this point in the Beta (0.77).
It is relatively early in the game. I have my capital city at about level 4 (no other cities yet). I decide I need to take a City from, my too close for comfort neighbor, Yithril. So I gather a decent army consisting of my soveriegn (level 4), two defenders, and two featherwyn archers.
I march my army right to the doorstep of this Yithril expansion City, declare war, and Mr Verga proceeds to come out to meet me with a comparable army. Only he doesn't attack. He passes right by me. I initially treat this action as just another example of the infancy of the current AI. I mean, Verga abandoned his city taking 3/4 of his army with them going who knows where?? Well my curiousity got the better of me and I decided to pursue Verga and see where he thought was so important to go to. I pursued him for about two turns when it suddenly occurred to me what that sneaky Verga was up to.
He was marching his army south around the lake and then up north to my, now poorly defended, capital city. At this point I halted my pursuit and made a beeline back to my city. Unfortunately at Verga's current pace I wasn't going to be able to make it back in time. A quick check of the city's defenses showed I had a low level 2 champion, two militia units, and one defender protecting the city. This defense barely held on and successfully defended the city, but took heavy casualties. I eventually went on to take Verga's expansion city.
Now this is where Verga's supposed brilliance turns to dimwittedness. Ever since I took his expansion city he consistently marches down from his main city, all by himself, and attempts to destroy my improvements. It takes very little effort on my part to kill him and send him back to his city. I have counted 3 occassions where he has done this.
That brief moment where I thought I may lose my one and only city due directly to an aggressive AI action are the moments I relish in strategy games. I hope that once the final AI is implemented in the months to come, I will be experiencing these types of moments throughout an entire game.